Climate variations over the Northern Hemisphere are to a substantial proportion associated with the North Atlantic Oscillation (NAO). Here, meta-analysis techniques were used for a quantitative synthesis on literature findings. The influence of the NAO on the timing of life history events, on biomass of organisms, and on biomass on different trophic levels was tested. A significant, clear NAO signature in freshwater, marine and terrestrial ecosystems was found. The response of life history events to the NAO was similar in all environments but less pronounced at higher latitudes. The magnitude of the biomass response was significantly related to the NAO, either positively in aquatic (lakes and oceans) or negatively in terrestrial ecosystems. The results stressed that a meta-analysis is a valuable tool in the field of climate-driven ecosystem responses and can identify more general ecological mechanisms than single studies. The inclusion of non-significant results is recommended in order to archive an objective view of the strength of NAO and climate impacts in general.